Density of States-Based DC I-V Model of Amorphous Gallium-Indium-Zinc-Oxide Thin-Film Transistors

The density of states (DOS)-based DC I-V model of an amorphous gallium-indium-zinc oxide (a-GIZO) thin-film transistor (TFT) is proposed and demonstrated with self-consistent methodologies for extracting parameters. By combining the optical charge-pumping technique and the nonlinear relation between the surface potential (phi(S)) and gate voltage (V(GS)), it is verified that the proposed DC model reproduces well both the measured V(GS)-dependent mobility and the I(DS)-V(GS) characteristics. Finally, the extracted DOS parameters are N(TA) = 4.4 x 10(17) cm(-3) . eV(-1), N(DA)= 3 x 10(15) cm(-3) . eV(-1), kT(TA) = 0.023 eV, kT(DGA) = 1.5 eV, and E(O) = 1.8 eV, with the formulas of exponential tail states and Gaussian deep states.